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(No Model.) I

H. W. JOHNS.

BOILER 0R PIPE COVERING.

No. 433,470. Patented Aug. 5, 1890.

ma NORRIS PETERS cu, Panto-Linux, WASHINGTON, o c.

UNITED STATES PATENT OFFICE.

HENRY W. JOHNS, OF NEW YORK, N. Y.

BOILER OR PIPE "COVERING.

SPEC'I'FICATION forming part of Letters Patent No. 433,470, dated August5, 1890.

Application filed December 12, 1889. Serial No. 333,559- (No model.)

To all whom it may concern:

Be it known that I, HENRY \VARD JOHNS, a citizen of the United States,and a resident of New York city, in the county of New York and State ofNew York, have invented a certain new or useful Boiler or Pipe Covering,of which the following is a specification.

My invention relates to an improvement in boiler or hot pipenon-conducting coverings; and it consists in the peculiarconstruction ofa compound sheet or covering hereinafter described.

The drawing illustrates a vertical section of my improved covering.

I first make a sheet or board, so called, of cut, picked, or shreddedsponge and paper stock, which may be made into sheet or board form bypulping the comrninuted sponge and paper'stock in an ordinarypaper-makers apparatus, and then make it into sheet form by any suitableapparatus or in any other pre ferred manner. The sheet thus produced hascertain characteristics which peculiarly adapt it to the describedusesto wit, it is very light, very porous, pliable, bulky in proportionto weight of material, elastic, and inexpensive; but when placed uponsurfaces which subject it to a considerable heat the paper-stock, andfrequently, also, the sponge will char. Thus the covering soon becomesuseless, and in some instances has been known to take fire. In order,therefore,'that the peculiarly-valuable qualities of the sponge andpaper-stock sheet or board may be utilized without the disadvantagesabove recited, I fire-proof the same by attaching to one or, if

desired, bothsides of the said sheet a coating or nap of fibrousasbestus by cementing the same thereto with silicate of soda or othercementing material, preferably, but not necessarily, fire-proof. Theresulting fabric is somewhat similar to that which would be produced byattaching a surface layer of lambs wool to a heavy felt, and ispeculiarly well adapted to the uses described.

It will be noticed that in my improved covering the asbestos ispermanently attached to the pulp and sponge layer. Thus separation ofthe fireproofing material from it is impossible, and they may both beapplied to the pipe by one and the same operation.

In the drawing, A represents the sheet formed of sponge and paper-stock,and B B represent the surface-layers of fibrous asbestus, that marked Bbeing of longer staple than the other. Of course the asbestus may be ofsuch length of fiber as preferred.

I claim-- A compound covering fabric consisting of an integral sheetcomposed of sponge and paper-stock and a coating of soft open or loosefibrous asbestus, the sponge and paper-stock constituting the body andthe asbestos the surface portions of the sheet, substantially asdescribed. I

Signed at New York, in the county of New York and State of New York,this 10th day of December, A. D. 1889.

HENRY WV. JOHNS.

YVitnesses:

PHILLIPS ABBOTT, FREDERICK SMITH.

